Chapter 15, Problem 23A

Solution

To determine:

The term that describes the scenario in which “One species evolve over millions of years to become two different but closely related species”.

Introduction:

Species can be defined as a group of individuals or very closely related organisms that are similar to each other and are capable of exchanging genes and interbreeding and producing fertile offspring.

The formation of new different species in the course of evolution is known as speciation.

A population must be diverged and then be reproductively isolated for the speciation to occur. There are mainly two types of speciation recognized by biologist,

Sympatric speciation: A species evolves into new species without a physical barrier. The ancestor and new species live side by side during the speciation process. They share the same geographical area but are reproductively isolated. This phenomenon occurs most commonly through polyploidy.

Allopatric speciation: A physical barrier divides one population into two or more population. The separate population will no longer be able to breed successfully with one another. The population is separated geographically and hence evolves separately.

The given scenario can be described by the term sympatric speciation.